Genetic analysis of fiber quality traits in short season cotton (Gossypium hirsutum L.)

Abstract

Six short season cotton cultivars (Gossypium hirsutum L.) were crossed in a dillalel crossing system to evaluate inheritance and interrelationship of phenotype and genotype of fiber quality traits (fiber length, uniformity index, fiber strength, micronaire and fiber elongation) and their correlation with earliness and yield traits. The study was carried out from year 2005 to 2008. The experiment design was a randomized complete block design with three replications. Additive, dominance and epistasis effects were analyzed with ADAA model. The results showed that fiber quality traits were mainly controlled by dominant genetic effects and also had a definitely proportion additive genetic effects. Micronaire, fiber length, fiber strength and fiber elongation had the highest broad sense heritability (HB) and by environment interaction (HBE) estimates, 0.618 (HB) and 0.267 (HBE) for micronaire, 0.510 (HB) and 0.287 (HBE) for fiber length, 0.452 (HB) and 0.316 (HBE) for fiber strength, 0.294 (HB) and 0.494(HBE) for fiber elongation, respectively. Narrow sense heritability (HN) was 0.258 for fiber elongation, 0.136 for fiber length, 0.127 for fiber strength and 0.110 for micronaire. Some F1 hybrids (A1×B2), (A2×A3) and (B1×A3) for fiber length, F1 (A2×B3) and (B1×B2) for fiber strength, F1 (B1×A2), (A2×B2), (A2×B3), (B1×A3), (B2×A3) and (B1×B2) for micronaire and F1 (A1×A2), (A1×A3), (A1×B1), (A1×B3) and (B2×A3) for fiber elongation had significant positive heterozygous dominance effects and affected by environment. Some F1 hybrids (A1×A2), (A1×B1), (A1×B3), (B1×A2) and (B2×A3) for fiber length, (A1×A3), (A1×B1) and (A1×B3) for fiber strength, (A1×A3), (A1×B1), (A1×B2) and (B2×B3) for micronaire and (A2×A3), (A2×B2), (A2×B3) and (B1×B2) for fiber elongation had significant positive epistatic effects. Among fiber quality traits, fiber length with fiber strength, uniformity index with fiber strength and micronaire, fiber strength with micronaire showed a positive and significant correlation. Only elongation had a significant negative correlation with fiber quality traits. Fiber quality traits had a negative correlation with earliness traits except micronaire. Fiber length and strength showed a significant negative correlation with lint yield, lint yield before frost, lint percentage and boll number. Uniformity index, micronaire and fiber elongation had a significant positive correlation with yield traits except boll weight and lint percentage. The results showed that the higher the yield and the earlier the maturing and the worse the fiber quality. Therefore, selections of fiber properties and integration of high yield, good fiber quality and early maturing traits should be performed in higher generations in short season cotton variety breeding program.